5 October 2006

A research consortium of six Japanese firms and the government are moving forward to commercialize a lower-cost Gas-to-Liquids process that does not require first removing carbon dioxide from a natural gas feedstock. (Earlier post.)

The immediate goal is to build a 500-barrel-per-day pilot plant in Japan, followed by a 30,000-bpd commercial plant near a gas field. A 7-bpd demonstration plant has been in operation for several years.

JOGMEC has been developing this natural gas to liquids (GTL) conversion technology since 1998 in collaboration with JAPEX, Chiyoda, Cosmo, Nippon Steel and INPEX Corp.

The new GTL process is particularly effective when applied to natural gas feedstock containing 20-40mol% of CO2. The process eliminates the need for three expensive components:

An oxygen supply plant;

A unit for CO2 separation; and

A H2 separation unit to optimize gas composition.

The most preferable CO2 content in the feedstock is around 30mol%. In case the CO2 content is less than 30mol%, additional CO2 can be supplied from other sources, such as flare gas, associated gas, remaining CO2 from Enhanced Oil Recovery operations or exhaust gas from oil refineries or LNG plants.

The process differs from other conventional GTL processes in two main ways. First, syngas is produced by steam (H2O)/CO2 reforming rather than autothermal reforming (ATR) or non-catalytic partial oxidation (POX) used in other processes. Second, the Fischer-Tropsch synthesis uses a slurry reactor with noble metal or non-noble metal catalysts, as compared to the copper or iron-based catalysts used in conventional processes.

Nippon Steel Corporation (NSC) developed the FT technology used in the process, and Chiyoda developed the catalysts.

Many gas fields—such as those in Southeast Asia—are rich in CO2 and therefore difficult to develop commercially. As an example cited by one of the partners, JAPEX, the Natuna gas field in Indonesia has reserves of more than 200 TCF. Due to its high CO2content (70%), however, the separation cost would have a major negative impact on the feasibility of the development.

The JOGMEC-GTL process is thus being targeted at such fields that would otherwise prove uneconomical to produce.